SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e762788cac8d7653258b3faf62e316a415e31cb9eaebc538f172b05fe42f7ae7' 
  AND token = 'YC94imjGPSRBHo5D/+U50UwXNL7BCqQq1JExL/zcchA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}